JP2010085540A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of obtaining an efficient cooling effect by reducing the air volume loss of a cooling gas. <P>SOLUTION: The image forming apparatus includes a cooling structure for cooling a processing unit 4 arranged in an apparatus body 100 by a gas. The cooling structure includes unit-side cooling ducts 46, 47 and 48 disposed in the processing unit 4; body-side cooling ducts 60, 61 and 62 attached to the apparatus body 100, guiding the gas into the unit-side cooling ducts 46, 47 and 48 and having a flow path cross-sectional area different from that of the unit-side cooling ducts 46, 47 and 48; and duct connecting members 70, 71 and 72 connecting the unit-side cooling ducts 46, 47 and 48 and the body-side cooling ducts 60, 61 and 62, to communicate them. The duct connecting members 70, 71 and 72 have a tapered flow path for communicating the flow paths of the unit-side cooling ducts 46, 47 and 48 and the flow paths of the body-side cooling ducts 60, 61 and 62. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a processing unit that performs a predetermined process when forming an image on a recording medium, for example, a developing device.

  In the image forming apparatus, suppressing the temperature rise of the developer in the developing device during the image forming process is one of effective means for obtaining a high-quality image. As a means for suppressing the temperature rise of the developer, for example, one disclosed in Patent Document 1 is known.

The image forming apparatus of Patent Document 1 uses a cooling duct to cool the developer in the developing device. Specifically, as shown in FIG. 9, the developing device side cooling disposed in the developing device 105. The cooling structure includes a duct 110 and a main body side cooling duct 112 that is attached to the apparatus main body side and communicates with the upstream side and the downstream side of the developing device side cooling duct 110. By allowing air to flow through the cooling duct 110, the developer in the developing device is cooled.
JP 2006-139045 A

  In the image forming apparatus of Patent Document 1, the flow passage cross-sectional area of the developing device side cooling duct 110 is large, and the flow passage cross sectional area of the main body side cooling duct 112 is small. Therefore, a step is generated between the developing device side cooling duct 110 and the main body side cooling duct 112. In general, such a step occurs because the developing device side cooling duct 110 is required to increase the cooling capacity, while the main body side cooling duct 112 is provided with a member around the developing device 105 such as an electric wiring or the like. This is because space constraints are imposed by the drive system members of the developing device.

  Due to this step, air swirls are generated on the upstream side and the downstream side of the developing device side cooling duct. Since this swirl hinders air flow, air volume loss occurs. In order to compensate for this air flow loss, it is conceivable to increase the air flow rate. However, if this is done, the amount of energy consumed will increase by the amount of air flow increase.

  In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of reducing the airflow loss of cooling gas and exhibiting an efficient cooling effect.

  In order to achieve the above object, an image forming apparatus according to the present invention includes an apparatus main body, a processing unit that is disposed in the apparatus main body and performs predetermined processing when forming an image on a recording medium, and the processing unit. And a cooling structure for cooling with gas. The cooling structure includes a unit-side cooling duct disposed in the processing unit, and a gas flow cross-sectional area of the unit-side cooling duct that is attached to the apparatus main body and guides the gas into the unit-side cooling duct. A main body side cooling duct having a different flow path cross-sectional area, and a duct connecting member that connects the unit side cooling duct and the main body side cooling duct to connect the two ducts. The duct connecting member has a tapered flow path that connects the flow path of the unit side cooling duct and the flow path of the main body side cooling duct.

  According to the image forming apparatus of the present invention, both the cooling ducts are formed by the tapered flow path portion of the duct connecting member even when the flow path cross-sectional areas of the unit side cooling duct and the main body side cooling duct are different. Both cooling ducts can be connected without causing a step between the flow paths. Thereby, when there is a step between both the ducts, it is possible to suppress the generation of a spiral that may be caused by the flow of gas in the vicinity of the step. As a result, it is possible to provide a cooling structure with little airflow loss and high cooling effect.

  In a preferred embodiment of the present invention, the channel cross-sectional area of the unit side cooling duct is set larger than the channel cross sectional area of the main body side cooling duct.

  Since the electrical wiring of the processing unit and the drive system member of the processing unit exist around the main body side cooling duct, it is difficult to increase the flow path cross-sectional area of the main body side cooling duct. However, according to the cooling structure of the image forming apparatus according to the present invention, even if the flow path cross-sectional area of the main body side cooling duct cannot be increased, the flow path breakage of the unit side cooling duct is caused by the tapered flow path portion of the duct connecting member. Since the area can be increased, the cooling effect of the processing unit by the unit side cooling duct is further enhanced.

  In another preferred embodiment of the present invention, the duct connecting member has a first gas flow path having a flow path cross-sectional area substantially the same as the flow path cross-sectional area of the main body side cooling duct, and the main body side cooling duct is A unit fitted with the unit-side cooling duct, having a body-side fitting portion to be fitted, and a second gas channel having a channel cross-sectional area substantially the same as the channel cross-sectional area of the unit-side cooling duct A side fitting portion is included, and the space between the first gas flow path and the second gas flow path is configured as the tapered flow path.

  In another preferred embodiment of the present invention, the image forming unit is a developing device, and the developing device can store the developer used for image forming processing and can convey the developer while stirring. A developer storage portion, a developer carrier that receives the developer from the developer storage portion and carries the developer, and the developer that the developer carrier receives from the developer storage portion. And a developer regulating member that regulates the amount.

  In still another preferred embodiment of the present invention, the developing device further includes a first portion extending into the developer reservoir and a second portion different from the first portion in the unit side cooling duct. The extending heat dissipation member is included. Since the developer is agitated in the developer reservoir, it generates frictional heat. According to this configuration, the second portion of the heat dissipation member extends into the unit-side cooling duct having a high cooling effect. It is possible to promote the heat dissipation of the developer.

  In still another preferred embodiment of the present invention, the developer regulating member of the developing device has a first portion in contact with the developer on the developer carrying member and a second portion different from the first portion. It extends in the unit side cooling duct. According to this configuration, since the second portion of the developer regulating member extends in the unit-side cooling duct having a high cooling effect, the developer can dissipate heat generated on the developer carrier. Is possible.

  In still another preferred embodiment of the present invention, the developer storage portion of the developing device is configured by a space partitioned by a wall portion, and the unit side cooling duct is provided through a part of the wall portion. ing. According to this configuration, since the unit-side cooling duct having a high cooling effect is provided on the wall portion constituting the developer storing portion, the developer that is agitated in the developer storing portion to generate heat of friction is radiated. It is possible to promote.

  According to the image forming apparatus of the present invention, both the cooling ducts can be connected without causing a step between the cooling ducts by the tapered flow path portion of the duct connecting member. Thereby, when there is a step between both cooling ducts, it is possible to suppress the occurrence of vortex that may be generated by the gas flowing in the vicinity of the step. As a result, it is possible to provide a cooling structure with little airflow loss and good cooling efficiency.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view schematically showing a configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus may be, for example, a printer, a copier, a facsimile machine, or a complex machine thereof. In the present embodiment, a case where the image forming apparatus is a printer will be described. Further, although the image forming apparatus is described as a monochrome printing printer, it may be a tandem color printing printer.

  The image forming apparatus includes an apparatus main body 100. The apparatus main body 100 includes an image forming unit 1 that forms a toner image on a recording medium such as paper P based on image data transmitted from an external device such as a computer, and paper. A fixing unit 13 that performs a fixing process for fixing the toner image on P to the sheet P, a sheet storage unit 10 that stores the sheet P, and a sheet discharge unit 14 that discharges the sheet P on which the fixing process has been performed. Have.

  The image forming unit 1 includes a photosensitive drum 2 on which an electrostatic latent image and a toner image along the electrostatic latent image are formed on the peripheral surface, and a charger 3 that uniformly charges the peripheral surface of the photosensitive drum 2. A nip portion is formed between the developing device 4 that supplies toner (developer) to the electrostatic latent image on the peripheral surface of the photosensitive drum 2 and the photosensitive drum 2, and the paper that has passed through the nip portion. A transfer roller 5 for transferring a toner image to P, a cleaning unit 6 for removing residual toner on the circumferential surface of the photosensitive drum 2 to clean the circumferential surface, and a removal for removing residual potential on the photosensitive drum 2. And an electric appliance 7. The charger 3, the developing device 4, the transfer roller 5, the cleaning unit 6, and the static eliminator 7 are arranged along the periphery of the photosensitive drum 2 and along the rotation direction indicated by the arrow of the photosensitive drum 2. In addition, the image forming unit 1 includes an exposure unit 8 that is disposed above the photosensitive drum 2 and exposes the peripheral surface of the photosensitive drum 2.

  The fixing unit 13 includes a heating roller 13a having an energized heating element serving as a heating source therein, and a pressure roller 13b disposed opposite to the heating roller 13a. Between the heating roller 13a and the pressure roller 13b, the paper P Is formed.

  In addition, a sheet conveyance path 12 for conveying the sheet P in the order of the sheet storage unit 10, the image forming unit 1, the fixing unit 13, and the sheet discharge unit 14 is formed inside the apparatus main body 100. Inside the apparatus main body 100, a paper feeder 20 that can feed out the paper P one by one from the paper storage unit 10 is further provided.

  Image forming processing by the image forming apparatus is performed as follows. After the peripheral surface of the photosensitive drum 2 is uniformly charged by the charger 3, the peripheral surface is exposed by irradiating the peripheral surface of the photosensitive drum 2 with laser light 9 based on the image data. . Thereby, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 2. Next, toner is supplied from the developing device 4 to the electrostatic latent image to develop the electrostatic latent image. As a result, a toner image is formed on the peripheral surface of the photosensitive drum 2. Thereafter, when the paper P conveyed from the paper storage unit 10 through the paper conveyance path 12 passes through the nip portion between the photosensitive drum 2 and the transfer roller 5, the toner image is transferred onto the paper P. During this transfer, a transfer bias is applied between the photosensitive drum 2 and the transfer roller 5 to smoothly move the charged toner onto the paper P.

  Next, the sheet P onto which the toner image has been transferred is conveyed to the fixing unit 13 and is subjected to a fixing process by obtaining heat from the heating roller 13a while passing through the nip portion between the heating roller 13a and the pressure roller 13b. The The paper P on which the fixing process has been performed is discharged to the paper discharge unit 14.

  After the toner image is transferred from the photosensitive drum 2 to the paper P, the toner remaining on the circumferential surface of the photosensitive drum 2 is collected by the cleaning unit 6, and then the residual potential on the circumferential surface of the photosensitive drum 2. Is erased by the static eliminator 7. Thereafter, the photosensitive drum 2 is charged again by the charger 3, and the above-described image forming process is repeated.

  In this specification, “developer” is a two-component developer composed of “toner” and “magnetic carrier”, but “developer” is a one-component system composed of only toner. It may be.

  By the way, in the image forming apparatus having the above-described configuration, for example, the developing device 4 of the image forming unit 1 generates heat along with the image forming process. As will be described later, since the developing device 4 that stores the developer supplies the developer to the photosensitive drum 2 while stirring, the developer generates frictional heat by the stirring operation. Due to this frictional heat, the temperature of the developer rises, and the fluidity is lowered or the chargeability is lowered. As a result, it becomes difficult to form a high-quality toner image on the photosensitive drum 2. Therefore, it is necessary to cool the developer in the developing device 4 in order to improve the image quality of the toner image. As a means for this, in the present embodiment, the developing device 4 is provided with a cooling structure. The cooling structure includes unit side first to third cooling ducts 46, 47, 48 disposed in the developing device 4, main body side first to third cooling ducts 60, 61, 62 disposed on the apparatus main body 100 side, The unit side first to third cooling ducts 46, 47, 48 and the main body side first to third cooling ducts 60, 61, 62 are configured to include first to third connection ducts 70, 71, 72. . Hereinafter, the cooling structure will be described together with the structure of the developing device 4.

  2 and 3 are an external perspective view of the developing device 4 provided with a cooling structure as viewed from the front and an external perspective view of the developing device 4 as viewed from the rear. The developing device 4 includes a developing container 45 that defines an internal space of the developing device 4 and extends in the front-rear direction of the device main body 100 (perpendicular to the paper surface of FIG. 1). The developer container 45 extends in the front-rear direction, and covers a magnet cover 56 and the like, which will be described later, from the right side and the upper side, and extends in the front-rear direction. Etc. from the left side, a front side plate 45c covering the front end 4a (FIG. 4) of the developing device 4 in the front-rear direction, and a rear side covering the rear end 4b of the developing device 4 in the front-rear direction. It has a side plate 45d and a bottom plate 45e.

  FIG. 4 is an external perspective view of the developing device 4 as viewed from the rear. For ease of explanation, the front plate 45c and the rear plate 45d are omitted and the external appearance of the developing device 4 is simplified. . In the internal space of the developing device 4, three unit side first cooling ducts 46 extending in the longitudinal direction (that is, the front-rear direction of the apparatus main body 100) from the front end 4 a to the rear end 4 b of the developing device 4, the unit A side second cooling duct 47 and a unit side third cooling duct 48 are arranged. The unit side first to third cooling ducts 46, 47, 48 are supplied with a cooling gas, for example air, from main body side first to third cooling ducts 60, 61, 62 described later.

  FIG. 5 is a cross-sectional view taken along line VV in FIG. 2, and shows the internal configuration of the developing device 4 and the arrangement of the unit side first to third cooling ducts 46, 47, 48. The developing device 4 stores a developer containing toner in an internal space thereof, and a developer storing portion 41 that can transport the developer while stirring, and a peripheral surface of the photosensitive drum 2. A developing roller 42 that supplies toner (developer) to form a toner image on the peripheral surface, a magnet roller 56 that faces the developing roller 42 and supplies the developer to the developing roller 42, and a developer reservoir The scooping roller 54 is disposed above the magnet 41 and in the vicinity of the magnet roller 56, pumps up the developer from the developer reservoir 41 and supplies the developer to the magnet roller 56, and feeds the developer from the developer reservoir 41 to the magnet roller 56. A developer regulating blade (developer regulating member) 55 that regulates the amount of the developer to be produced. In the present embodiment, the developing roller 42 and the magnet roller 56 constitute a developer carrier that carries the developer. Further, the developing roller 42, the magnet roller 56, and the pumping roller 54 are similar to the unit side first to third cooling ducts 46, 47, and 48, so that each axis extends in the longitudinal direction of the developing device 4. 4 is disposed inside.

  The developer storage unit 41 includes two adjacent developer storage chambers 41a and 41b extending in the longitudinal direction of the developing device 4, and the developer storage chambers 41a and 41b are partition plates made of metal such as aluminum, for example. 50 are separated from each other in the longitudinal direction, but communicate with each other at both corners in the longitudinal direction. Further, screw feeders 43 and 44 for stirring the developer by rotation are rotatably mounted in the developer storage chambers 41a and 41b. Since the screw feeders 43 and 44 are set so that the conveyance directions are opposite to each other, the developer is conveyed between the developer storage chamber 41a and the developer storage chamber 41b while being stirred. Further, a toner receiving port (FIG. 2) 38 protruding forward from the front side plate 45c of the developing container 45 is attached to the developer storing chamber 41a, and the developer storing portion 41 is provided from a toner cartridge (not shown). The toner is received through the toner receiving port 38.

  The developer regulating blade 55 is a plate member extending in the longitudinal direction of the developing device 4, and development supplied from the magnet roller 56 by regulating the amount of developer magnetically attached to the peripheral surface of the magnet roller 56. The amount of the agent is regulated. A slight gap of a predetermined size is formed between the tip 55a of the developer regulating blade 55 and the peripheral surface of the magnet roller 56, and when the magnet roller 56 rotates, the developer passes through the developer in the gap. It is regulated by the tip 55a of the regulation blade 55. As a result, a developer layer having a predetermined thickness is uniformly formed on the peripheral surface of the magnet roller 56.

  The unit-side first cooling duct 46 is a duct extending in the longitudinal direction along the upper left corner of the inner space of the developing device 4, and is a bottom wall formed of a substantially inverted U-shaped duct body 46a and a part of the left side plate 45b. 46b. A space surrounded by the duct main body 46 a and the bottom wall 46 b becomes a flow path of the unit-side first cooling duct 46. In the flow path of the unit side first cooling duct 46, the partition plate 50 of the developer storage section 41 is disposed. Specifically, one end (first portion) 50a of the partition plate 50 is disposed between the developer storage chambers 41a and 41b so as to partition the developer storage chambers 41a and 41b, while the other end ( The shape of the second portion 50 b is set so as to extend into the unit-side first cooling duct 46. The shape is set to an inverted U shape in FIG. 5, but is not particularly limited.

  The unit-side second cooling duct 47 is a duct extending in the longitudinal direction along the upper right corner corresponding to the upper portion of the magnet roller 56 in the internal space of the developing container 45, and the main cover 45a of the developing container 45 and the developer. The flow path is defined using the regulation blade 55. Specifically, a part of the main cover 45a corresponding to the upper portion of the magnet roller 56 is formed into a substantially U shape, and the opening side of the substantially U-shaped portion 45aa is excluded from the tip end portion 55a of the developer regulating blade 55. The unit side second cooling duct 47 is configured by being blocked by the main body portion 55b.

  The unit side third cooling duct 48 is formed integrally with the bottom plate 45 e of the developing container 45. Specifically, the bottom plate 45e is made of, for example, aluminum, and defines the developer storage chambers 41a and 41b of the developer storage unit 41 together with the left side plate 45b, and the bottom plate 45e includes the developer storage unit 41 of the developer storage unit 41. A flow path that penetrates the bottom plate 45e is provided so as to extend in the longitudinal direction at the lower position. This flow path constitutes the unit side third cooling duct 48. In addition, in FIG. 5, although the four flow paths comprise the unit side 3rd cooling duct 48, the number of flow paths is arbitrary.

  2 and 3, each of the front side plate 45 c and the rear side plate 45 d has the unit side first to third cooling at positions corresponding to the unit side first to third cooling ducts 46, 47, 48. First to third duct connecting members 70, 71, 72 for connecting ducts 46, 47, 48 and main body side first to third cooling ducts 60, 61, 62 (FIG. 6) described later are integrally formed. ing. The first to third duct connecting members 70, 71, 72 have a cross-sectional shape corresponding to the cross-sectional shape of the unit-side first to third cooling ducts 46, 47, 48. In addition, instead of integrally forming the first to third duct connecting members 70, 71, and 72 on the front plate 45c and the rear plate 45d, unit side first to third cooling in the front plate 45c and the rear plate 45d. Openings may be formed at positions corresponding to the ducts 46, 47, and 48, and the first to third duct connecting members 70, 71, and 72 may be fitted into these openings.

  FIG. 6 is a perspective view of the main body side first to third cooling ducts 46, 47 and 48 connected to the first to third duct connecting members 70, 71 and 72. The main body side first to third cooling ducts 60, 61, 62 shown in the figure are set so as to pass through predetermined through holes formed in the assembly frame 80 on the apparatus main body 100 side to which the developing device 4 is assembled. The first to third duct connecting members 70, 71, 72 (FIG. 3) formed on the rear side plate 45d of the developing container 45 are connected. That is, the main body side first cooling duct 60 is connected to the first duct connecting member 70, the main body side second cooling duct 61 is connected to the second duct connecting member 71, and the main body side third cooling duct 62 is connected to the first duct connecting member 70. It is connected to the 3-duct connecting member 72. The main body side first to third cooling ducts (not shown) are similarly connected to the first to third duct connecting members 70, 71, 72 (FIG. 2) formed on the front side plate 45c of the developing container 45. The The main body side first to third cooling ducts 60, 61, 62 are connected to a common duct (not shown) on the upstream side, and are cooled from a common cooling gas supply device (a blower when the cooling gas is air). It is preferable to receive supply of gas. If the cooling gas flows from the front side to the rear side of the developing device 4, for example, the main body side first to third cooling ducts 60, 61 and 62 shown in FIG. It becomes a duct on the downstream side from which the cooling gas passing through the ducts 46, 47, 48 is discharged. The main body side first to third cooling ducts 60, 61, 62 on the upstream side and the main body side first to third cooling ducts 60, 61, 62 on the downstream side have the same shape.

  The assembly frame 80 has a through hole 81 at a position below the main body side first cooling duct 60 and the main body side second cooling duct 61 and above the main body side third cooling duct 62. A rotational force transmitting member 82 connected to a drive source (not shown) that applies rotational driving force to the screw feeder 44 of the developer storage chamber 41b of the developing device 4 is inserted. The rotational force transmitting member 82 is connected to a connecting member 84 (FIG. 3) attached to the rear end portion of the screw feeder 44 to transmit the rotational force to the screw feeder 44. Since the assembly frame 80 is provided with various members and electrical wiring for assembling the developing device 4 to the assembly frame 80 in addition to the rotational force transmitting member 82, the developing device 4 is attached to the assembly frame 80. In the assembled state, the space between the rear side plate 45d of the developing device 4 and the assembled frame 80 is extremely narrow. Further, the space between the front side plate 45c of the developing device 4 and the assembly frame 80 is extremely narrow for the same reason.

  Next, the connecting structure of the unit side first to third cooling ducts 46, 47, 48 and the main body side first to third cooling ducts 60, 61, 62 in the cooling structure will be described. FIG. 7 is a cross-sectional view of the connecting structure between the unit-side first cooling duct 46 and the main body-side first cooling duct 60 as a representative example, as viewed from above the developing device 4. In the following description, it is assumed that the cooling gas flows from the front (that is, upstream) to the rear (that is, downstream) of the developing device 4 as indicated by an arrow. The first duct connecting member 70 includes an upstream connecting member 73 and a downstream connecting member 74. The upstream side connection member 73 (the lower side connection member in FIG. 7) is a unit having a gas cross-sectional area different from the gas cross-sectional area of the gas outflow part 63 of the main body side first cooling duct 60 and the gas outflow part 63. It is a member that connects the upstream end 46c of the first side cooling duct 46, and has a gas flow path 75 that connects the flow path of the gas outlet 63 and the flow path of the upstream end 46c.

  Specifically, the upstream connecting member 73 has a gas inlet 73aa having a flow passage cross-sectional area substantially the same as the flow passage cross-sectional area of the gas outflow portion 63 of the main body side first cooling duct 60. Has a main body side fitting portion 73a and a gas outlet 73bb having a channel cross-sectional area substantially the same as the channel cross-sectional area of the unit-side first cooling duct 46. And a unit-side fitting portion 73b that can be fitted into the upstream end portion. The gas flow path 75 of the upstream connection member 73 is set so that the flow path cross-sectional area gradually increases from the gas inlet 73aa toward the gas outlet 73bb. In other words, the gas flow path 75 of the upstream connection member 73 is formed as a tapered flow path. In the present embodiment, the gas inlet 73aa and the gas outlet 73bb have a substantially rectangular shape, and the sides of the gas inlet 73aa and the sides of the gas outlet 73bb corresponding to the sides are continuous. Four tapered surfaces are formed. The shapes of the gas inlet 73aa and the gas outlet 73bb are not limited to a rectangle, and may be, for example, a substantially square. In that case, the four tapered surfaces to be configured have the same inclination angle.

  A seal member 85 made of urethane or the like is interposed between the gas outflow portion 63 of the main body side first cooling duct 60 and the main body side fitting portion 73a of the upstream side connection member 73 into which the gas outflow portion 63 is fitted. is doing. The upstream end 46c of the unit-side first cooling duct 46 is dimensioned so that the unit-side fitting portion 73b of the upstream connecting member 73 can be received via a seal member 86 made of urethane or the like. FIG. 8 shows a state in which the seal member 86 is affixed to the unit side fitting portion 73 b of the upstream side connection member 73.

  On the other hand, the downstream connecting member 74 (upper connecting member in FIG. 7) has a gas cross-sectional area different from the gas inflow portion 64 of the main body side first cooling duct 60 ′ and the gas inflow portion 64. It is a member that connects the downstream end 46d of the unit-side first cooling duct 46, and has a gas flow path 76 that connects the flow path of the gas inflow section 64 and the flow path of the downstream end 46d. Yes.

  The downstream side connection member 74 is a member having a mirror surface relationship with the upstream side connection member 73. Specifically, the downstream side connection member 74 has substantially the same flow path cross-sectional area as the gas inflow portion 64 of the main body side first cooling duct 60 ′. The main body side fitting portion 74a which has a gas outlet 74aa having a road cross-sectional area and into which the gas inflow portion 64 can be fitted, and the flow passage cross-sectional area substantially the same as the flow passage cross-sectional area of the unit-side first cooling duct 46 A unit-side fitting portion 74b that has a gas inlet 74bb and can be fitted into the downstream end 46d of the unit-side first cooling duct 46. The gas flow path 76 of the downstream connection member 74 is set so that the cross-sectional area of the flow path gradually decreases from the gas inlet 74bb of the unit side fitting portion 74b toward the gas outlet 74aa of the main body side fitting portion 74a. Has been. In other words, the gas flow path 76 of the downstream connection member 74 is formed as a tapered flow path.

  Similarly to the upstream side connection member 73, the downstream side connection member 74 connects the main body side first cooling duct 60 ′ and the unit side first cooling duct 46 via seal members 87 and 88. Specifically, between the gas inflow portion 64 of the main body side first cooling duct 60 ′ and the main body side fitting portion 74 a of the downstream side connecting member 74 to which the gas inflow portion 64 is fitted, urethane or the like is used. A sealing member 87 is interposed. The downstream end 46d of the unit-side first cooling duct 46 is dimensioned so that the unit-side fitting portion 74b of the downstream connecting member 74 can be received via a seal member 88 made of urethane or the like.

  According to the cooling structure configured as described above, even if the flow path cross-sectional areas of the unit-side first cooling duct 46 and the main body-side first cooling ducts 60, 60 ′ are different, the first duct The tapered flow paths 75 and 76 of the upstream connection member 73 and the downstream connection member 74 of the connection member 70 and the flow path of the gas outflow portion 63 of the main body side first cooling duct 60 and the unit side first cooling duct 46 are connected. Between the flow path of the upstream end 46c and between the flow path of the gas inlet 64 of the main body side first cooling duct 60 'and the flow path of the downstream end 46d of the unit side first cooling duct 46. The unit side first cooling duct 46 and the main body side first cooling ducts 60, 60 ′ can be connected without causing a step. Thereby, when there is a step between the unit-side first cooling duct 46 and the main body-side first cooling ducts 60, 60 ', it is possible to suppress the generation of a vortex that may be caused by the cooling gas flowing near the step. As a result, the cooling gas smoothly flows between the main body side first cooling duct 60 and the unit side first cooling duct 46 and between the unit side first cooling duct 46 and the main body side first cooling duct 60 '. It is possible to provide a cooling structure with little loss and good cooling efficiency.

  Further, the electrical wiring and drive system members of the developing device 4 exist between the developing device 4 and the assembly frame 80 to which the developing device 4 is assembled, that is, around the main body side first cooling ducts 60 and 60 '. Therefore, it is difficult to increase the cross-sectional area of the main body side first cooling ducts 60, 60 ′. However, according to the cooling structure, each of the upstream side connection member 73 and the downstream side connection member 74 of the first duct connection member 70 can be obtained even if the flow passage cross-sectional area of the main body side first cooling ducts 60, 60 ′ cannot be increased. Since the flow passage cross-sectional area of the unit side first cooling duct 46 can be increased by the tapered flow passages 75 and 76, the cooling effect of the developing device 4 by the unit side first cooling duct 46 is enhanced.

  The second duct connecting member 71 that connects the main body side second cooling duct 61 and the unit side second cooling duct 47 and the third main body side third cooling duct 62 and the unit side third cooling duct 48 that are connected. Since the duct connecting member 72 has substantially the same configuration as the first duct connecting member 70 described above except for its shape, detailed description of the second duct connecting member 71 and the third duct connecting member 72 is provided. Is omitted.

  Next, the effect | action with respect to the developing apparatus 4 of a cooling structure is demonstrated. As described above, the developing device 4 generates heat along with the image forming process. Specifically, the developer is stressed between the developer regulating blade 55 and the magnet roller 56 when the developer is cut off by the tip 55a of the developer regulating blade 55 in the gap between the developer regulating blade 55 and the magnet roller 56. Because it is applied, frictional heat is generated. Further, when the developer in the developer reservoir 41 is agitated by the screw feeders 43 and 44, the developers rub against each other and generate frictional heat. When the developer retains heat due to frictional heat, the charge amount of the developer is reduced. In addition, since the temperature in the developing device 4 also rises, the temperature of the toner contained in the developer also rises and is fused to the developer regulating blade 55 and the like, and the phenomenon that the developer layer is not uniformly formed is caused. appear. As a result, it becomes difficult to form a good toner image on the peripheral surface of the photosensitive drum 2. However, in the image forming apparatus according to the present embodiment, the unit-side first to third cooling ducts 46, 47, 48 of the cooling structure radiate such frictional heat and suppress the temperature rise in the developing device 4. ing.

  Specifically, the frictional heat generated by the developer agitation in the developer reservoir 41 is transmitted from one end 50a of the partition plate 50 to the other end 50b, and the other end 50b retains the frictional heat. become. Since the other end 50 b of the partition plate 50 is disposed in the unit-side first cooling duct 46, the frictional heat is radiated by the cooling gas flowing in the unit-side first cooling duct 46.

  Further, the heat generated by the developer carried on the peripheral surface of the magnet roller 56 is transmitted from the tip end portion 55a of the developer regulating blade 55 to the main body portion 55b, and the main body portion 55b retains heat. Since the main body portion 55 b of the developer regulating blade 55 is used as a member that defines the flow path of the unit-side second cooling duct 47, the heat of the main body portion 55 b flows in the unit-side second cooling duct 47. Heat is dissipated by the cooling gas.

  Further, the frictional heat generated by the developer agitation in the developer reservoir 41 is transmitted to the bottom plate 45e that defines the space of the developer reservoir 41, and the bottom plate 45e retains the frictional heat. Since the unit-side third cooling duct 48 is provided in the bottom plate 45e, the frictional heat is radiated by the cooling gas flowing in the unit-side third cooling duct.

  In this way, the unit-side first to third cooling ducts 46, 47, and 48 suppress the temperature rise in the developing device 4, and thus suppress the melting of the toner contained in the developer. As a result, a high-quality toner image is formed on the peripheral surface of the photosensitive drum 2.

  In the image forming apparatus according to the embodiment of the present invention described above, the case where three unit side cooling ducts 46, 47, 48 and three main body side cooling ducts 60, 61, 62 are used has been described. The number is not limited, and may be two or four as long as a desired cooling effect is obtained.

  Further, although the case where the cooling structure is applied to the developing device 4 has been described, the cooling structure may be applied to cleaning, for example.

1 is a front view schematically showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an external perspective view of a developing device provided with a cooling structure in the image forming apparatus as viewed from the front. It is the external appearance perspective view which looked at the developing device from back. FIG. 2 is an external perspective view of the developing device as viewed from the rear, and the external appearance of the developing device is simplified for easy explanation. It is sectional drawing cut | disconnected along the VV line | wire of FIG. 2, and has shown arrangement | positioning of the internal structure of a developing device, and the unit side 1st-3rd cooling duct of a cooling structure. It is a perspective view of the main body side 1st-3rd cooling duct connected to the unit side 1st-3rd cooling duct. FIG. 6 is a cross-sectional view of the connecting structure of the unit side first cooling duct and the main body side first cooling duct as a representative example, as viewed from above the developing device. It is a perspective view which shows the state by which the sealing member was affixed on the 1st duct connection member of the cooling structure. It is sectional drawing which looked at the conventional duct connection structure from upper direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image formation part 2 Photosensitive drum 4 Developing device 45 Developer container 46,47,48 Unit side 1st-3rd cooling duct 46c Upstream side edge part 60,61,62 Main body side 1st-3rd cooling duct 63 Gas outflow Portions 70, 71, 72 First to third duct connecting members 73 Upstream connecting member 73a Main body side fitting portion 73aa Gas inflow port 73b Unit side fitting portion 73bb Gas outflow port 74 Downstream side connecting member 75 Gas flow channel 80 set Attachment frame 85, 86 Seal member 100 Image forming apparatus main body

Claims (7)

The device body;
A processing unit that is disposed in the apparatus main body and performs predetermined processing when forming an image on a recording medium;
A cooling structure for cooling the processing unit with a gas;
With
The cooling structure is
A unit-side cooling duct disposed in the processing unit;
A main body side cooling duct attached to the apparatus main body to guide the gas into the unit side cooling duct and having a flow path cross-sectional area different from the flow path cross section of the unit side cooling duct;
A duct connecting member that connects the unit side cooling duct and the main body side cooling duct to connect both ducts;
Including
The said duct connection member is an image forming apparatus which has a taper-shaped flow path which connects the flow path of the said unit side cooling duct, and the flow path of the said main body side cooling duct.   The image forming apparatus according to claim 1, wherein a flow path cross-sectional area of the unit side cooling duct is set larger than a flow path cross sectional area of the main body side cooling duct. 3. The image forming apparatus according to claim 2, wherein the duct connecting member includes a first gas flow path having a flow path cross-sectional area substantially the same as a flow path cross-sectional area of the main body side cooling duct, and the main body side cooling duct. Has a main body side fitting portion and a second gas flow passage having a flow passage cross-sectional area substantially the same as the flow passage cross sectional area of the unit side cooling duct, and is fitted to the unit side cooling duct. Including a unit side fitting portion,
An image forming apparatus in which a space between the first gas channel and the second gas channel is configured as the tapered channel.   4. The image forming apparatus according to claim 1, wherein the image forming unit stores the developer used for the image forming process and can convey the developer while stirring. 5. A developer storage unit, a developer carrier that receives the developer from the developer storage unit and carries the developer, and an amount of the developer that the developer carrier receives from the developer storage unit An image forming apparatus, which is a developing device including a developer regulating member that regulates the above.   5. The image forming apparatus according to claim 4, wherein the developing device further includes a first portion extending into the developer storage portion and a second portion different from the first portion in the unit-side cooling duct. An image forming apparatus including an extending heat dissipation member.   5. The image forming apparatus according to claim 4, wherein the developer restricting member of the developing device has a first portion in contact with the developer on the developer carrying member and a second portion different from the first portion. An image forming apparatus extending into the unit side cooling duct.   5. The image forming apparatus according to claim 4, wherein the developer storage portion of the developing device is configured by a space partitioned by a wall portion, and the unit-side cooling duct is provided through a part of the wall portion. Image forming apparatus.

Images